This invention relates essentially to a spatial positioning apparatus providing three-dimensional position information and a method to utilize the position information for improved surveying, construction layout, equipment operations, manufacturing control and autonomous vehicle control.
Recently, a plurality of systems has been developed that only requires one person for the setting out when using a surveying equipment.
One kind of such equipment described in U.S. Pat. Nos. 5,100,229 and 5,110,202, having an applicant within the same group of companies as the applicant of this invention, comprises two, three or four referent stations on fixed positions at the area to be set out, each sweeping at least one spread beam vertically or obliquely towards the vertical plane across the site of interest. At least one portable position sensor, preferably provided on a staking-out rod is moved to different positions to be set-up or set out in the area to be monitored. Two or three portable sensors could be positioned on a working machine in order to keep track or the positions and orientations of the machine while in work. The portable sensor or sensors are provided with a computer system calculating the position of each measured position.
As illustrated in a user""s manual regarding the system VULCAN edited by the company ARCSECOND, which has set the system described in U.S. Pat. Nos. 5,100,229 and 5,110,202 on the market, two sensors are provided on a rod having a tip at an extension of the rod adapted to be placed mechanically to a measuring point inaccessible from the referent stations. The extended rod has a determined and rather short length, which limits the positions that the operator can take when measurements to inaccessible points have to be made.
Another kind of such equipment comprises a surveying instrument, for example a total station manufactured by Spectra Precision AB, positioned at a fixed point in the area to be surveyed. Such an instrument could have a person directing the instrument towards a reflector, for example provided with at least one cube corner prism. However, most often the surveying instrument has the ability to search for and automatically lock to a target which position is to be determined. Such a surveying instrument is often referred to as a robotic total station. The target can either be a simple reflector or a reflector combined with an active target (i.e. a modulated LED). In this measuring system the measurement results are transferred to the rod by for instance a radio communication link. The computer unit at the rod or in the instrument calculates the position of the target. The person at the rod can also transfer commands to the total station via the same radio link. As this type of systems is considered to be state of the art, no further description will be given of it here.
However, there are often some points within the area to be set-up or set out which could not be reached directly by the surveying equipment due to obstacles in the area, such as trees, buildings or the like. Other points can not be reached by a detector or target, because they are too high above ground or close to some other object like a wall or in a corner. It is therefore a need to be able to make measurement also to points inaccessible from referent stations according to the first kind of equipment, or to points that are unreachable with a detector or target.
One solution to the problem of measurement against a inaccessible point is to use GPS technology as described in the co-pending U.S. application Ser. No. 09/402258 (corresponding to EP-98914184.1), which means providing the surveying instrument and the staking rod with a GPS antenna (GPS=Global Position Satellite). This system will however not function indoors. The antenna is normally large and difficult to position close to other objects.
Another solution to the problem is described in EP 90/906405.7 in which a surveying instrument could be measuring the position of another surveying instrument, which in turn is directed to a reflector arrangement. This arrangement functions well but is labourous for the operator or the operators making the setting-out staking-out work.
A technical problem to be solved with the invention is to provide a relatively simple and low cost surveying system in which positions that are inaccessible from referent stations or a surveying instrument or that are unreachable with a detector or target could be measured in an easy way.
An object of the invention is to provide a surveying method and surveying system by which objects inaccessible or not reachable with a detector/target from referent stations or the like could be easily measured.
Another object of the invention is to provide a surveying method and surveying system by which only one person could provide the surveying operations to measure measuring points in a whole area to be surveyed.
Still another object of the invention is to provide a surveying method and surveying system by which an operator could make all the measures to measuring points in the area to be monitored by means of only one portable equipment.
The invention relates to a spatial positioning system having at least one stationary station means positioned in a field to be measured and providing referent site(s) in an area to be set-out or staked-out, and a portable position sensor means having at least two sensor elements. The sensor elements could be regarded as detectors or targets, the position of which could be directly determined. The position of each sensor element is indicated by a co-operation between the sensor element and said at least one stationary station means. The spatial positioning system comprises, in order to make said spatial positioning system able to measure to measuring points not reachable for said stationary station means, or by a sensor,
a distance meter provided in said portable position sensor means able to emit a visible beam to be directed towards a inaccessible point to be measured at least during an alignment operation towards said point and able to make a measurement to the point at control;
said sensor elements in the position sensor means having predetermined positions in relation to each other and to said distance meter for providing position of said distance meter and position and orientation of an alignment line towards said inaccessible point for said distance meter at control;
computer means for computing the position of the inaccessible point based on measurement of said distance meter, measured positions of said sensor elements and the spatial positions of the distance meter and said elements in relation to each other.
The sensor elements could be two and provided in line with said distance meter. As an alternative, the sensor elements could be at least three defining a plane. The distance meter has a predetermined position and orientation in relation to said sensor elements.
The at least one stationary station means could comprise at least two referent stations, each sweeping at least one spread beam across said area of interest, each sensor element including a light sensitive detector co-operating with a computer. The spatial position of each sensor element is then obtained through triangulation technique based on time marks received from each spread laser beam from said referent stations and indicated by said computer.
The at least one stationary station means could instead comprise a surveying instrument, and then each sensor element includes at least one target, to which the surveying instrument is automatically directed to measure and compute its position.
The advantage of the invention is that it is easy to handle by an operator working with staking-out or setting-out in an area. He or she need not provide different mounts of instruments in order to measure towards inaccessible or unreachable points. There are no limits other than accuracy as to the distance from the staking rod towards the inaccessible point to be measured. This makes the measuring task easy for the operator, who does not have to move to a position near to the inaccessible point when measuring its position.